Interview With Author Of New Barefoot Kenyan Running Study

Kevin Hatala is a graduate student at the Center for the Advanced Study of Hominid Paleobiology at George Washington University. He has a particular interest in human and primate gait. His student Web site states: “Specifically, he is interested in combining experimental biomechanical studies with analyses of the fossil record to better understand the evolutionary history of human locomotion.”

Below Hatala answers several questions about his paper. A recreational runner, he plans to enter his first half-marathon this spring.

You don’t appear to be a running biomechanist. How/why did you get interested in measuring footstrikes of Dasaanach?Kevin Hatala: My primary area of research is human evolutionary biology, and I am specifically interested in how human locomotion has evolved over the past several million years. I conduct experimental work aimed at understanding the biomechanics of human and primate locomotion, so that we can apply those results to better understand the human fossil record and answer questions about our evolutionary past.

In thinking about how human running may have evolved, we became curious about how modern habitually unshod people run, since the form and function of of the human foot evolved over millions of years during which it was unshod. There’s evidence that since we began wearing shoes, our toes have been pushed closer together. In barefoot populations, the toes are more spread out, more splayed. Also, the barefoot have thicker soft tissue mass at the bottom of the foot--not calloused, but thicker, and they distribute the forces of walking and running more evenly over more parts of the foot.

Previous research by the Lieberman group had shown that one population of unshod runners preferred a specific style of running, so we were curious if that pattern held true in the Daasanach as well.

Your findings seem mostly opposite of the Lieberman Nature report. Did this surprise you?KH: We were surprised by our findings. We found evidence to support the idea that a forefoot strike can reduce impact forces compared to a rearfoot strike, but very few of our habitually unshod volunteers naturally ran that way. They did move more to the midfoot and forefoot when they ran faster, but the majority were still striking on the rearfoot. We thought this pace element might be part of the answer, but Lieberman told us the Kalenjin don’t use the rearfoot much even at slow speeds.

What do you think primarily accounted for your rearfoot-strike findings?KH: There are likely many variables that together influence how people strike the ground when they run. These can include factors such as the characteristics of the running surface, or the running habits of individuals. We are now working in collaboration with the Lieberman lab at Harvard, to conduct further experiments and perform additional analyses, to figure out why the Daasanach appear to be so different from the Kalenjin that were studied in their Nature report.

How much time have you spent with the Dasaanach? Is there any running culture among this group? Anatomically (i.e., height, weight) are they very different from the Kalenjin? Are most of them barefoot? What kind of surface do they walk and run on?KH: We have spent several summers with the Daasanach, and I would say that there is not a clear "running culture" such as that which the Kalenjin are known for. Children are always running as they spend a great deal of time playing outdoors, but it is not common to encounter someone running purely for exercise. Anatomically, at least in terms of height and weight, the Daasanach seem to be very similar to the Kalenjin. Maybe half of the adult males begin wearing huarache-type sandals, but they grow up entirely barefoot. Most of the adult women and children are barefoot. Their environment is largely a firm sand surface. It has a little give, but it’s not at all like a beach sand.

What should we conclude from the different findings of your group and the Lieberman group?KH: Probably that there’s not one universal way of running that evolved for all peoples on all parts of the planet. It’s no doubt more complex than that. It depends on many factors, including the anatomy of the runners and the environment they live in. We’re beginning to develop a good relationship with the Lieberman team. We’re sharing our data sets, and working on ways to better understand the differences.

A Part of Hearst Digital Media
Runner's World participates in various affiliate marketing programs, which means we may get paid commissions on editorially chosen products purchased through our links to retailer sites.